Percy Jackson and the Book of Thanatos
by Zatcher
Summary: The Greek world falls into crisis and disarray when a vengeful Death Note user appears on the scene.
1. Rebirth

Percy's first thought when he woke up and realized he couldn't remember anything, was "_I'm going to kill Hera!_"

He sat at an empty table in the middle of a large, bustling cafeteria, probably at a mall somewhere, apparently eating what looked like a half-finished Big Mac with fries and Pepsi. Next to him was a backpack he didn't recognize, but which was obviously his, judging by the Camp Half-Blood logo sewn into it. And folded next to his food tray was a newspaper bearing the date, August 28th.

He clenched his fists in anger.

One month. No, according to the newspaper, not _even_ one month had passed since the war with the Giants, and already Percy's memory had been wiped out. _Again._

"No it hasn't," a voice said, and Percy nearly jumped out of his skin.

A familiar man had appeared next to him, casually munching on a subway sandwich. He had nylon running shorts and a New York City Marathon T-shirt. He was slim and fit, with salt-and-pepper hair and a sly smile.

"Hermes," Percy said.

"That's me," the god replied between chews.

_We're here, too!_ said a raspy voice, which Percy recognized as the snake George. _Did you bring me my rat yet?_

_Hush, George,_ said another voice, which Percy also recognized as Martha. _We're here on important business, don't interrupt!_

"Yes indeed," said Hermes, taking a sip of diet coke. Then he looked at Percy with a friendly smile. "So then. What was it you wanted to talk to me about?"

Percy blinked. He had no idea what was going on. He didn't remember getting to this cafeteria. He certainly didn't remember wanting to talk to Hermes. Was _that_ what he wanted to talk about, his memory? But then, of all the gods, why would he have contacted Hermes about it? Why not the Morpheus cabin? Or Chiron? Or better yet, the queen of amnesia, Hera the Inconvenient?

"Well," Percy said tentatively, "I guess I wanted to talk about my memory?"

Hermes raised an eyebrow. "What about it?"

"I think I lost it again."

Well, that was partially true. He didn't remember what he was doing in this cafeteria, but now that he thought about it, his memory wasn't _really_ gone – at least, not like last time. He remembered Annabeth quite clearly, thank goodness. He also remembered his friends. He remembered the camps, Gaea, the war with the giants, _winning_ the war with the giants, visiting New Rome with Annabeth, and then…

Percy's brain hurt. He remembered… a book. It was fuzzy, but he definitely remembered a book falling out of the sky, a visit from a god, and then… nothing. That's where his mind drew up a blank.

Hermes tapped his fingers over the table, giving Percy a meaningful look. "Your memory isn't gone Percy, it's still there. I can tell you that much."

"So you know what's happening?"

Hermes shook his head. "I received a prayer from you this morning asking to meet you here. It sounded like it was really important, so I came. Other than that, I have no idea what this is about." The god frowned and studied Percy more closely. "That's odd…"

Percy suddenly felt uncomfortable. "Are you reading my mind?"

"Hmm? Oh, sorry. No, not quite. Gods can't really read your mind, you know. We can sense your emotions pretty accurately, however. You'd be surprised how much can be gleamed of a person's mind from that." He took another sip of coke. "But there's something troubling about your memories at the moment. I can sense they haven't been taken, and they haven't been erased, either. They're all still there, just somewhat… suppressed. But it's not like anything I've ever seen before. Is this what you wanted to talk to me about?"

"Not sure," Percy replied. "I mean, I actually remember almost everything. Just not whatever's been happening the last few weeks. I don't know how I got here, or what I've been doing. I don't suppose you've noticed if Hera's been hatching any schemes lately?"

"None that I can think of," Hermes said. "But if I hear of anything, I'll be sure to let you know."

"Well then… Is there anything you can do about this? Maybe throw some Hermes magic my way and make my memories come back?"

Hermes frowned. "I'm afraid memories aren't really my area, Percy. But I suppose I can give it a try." He pulled a cellphone from his pocket and said, "Original form, please." The cellphone grew into a three foot long caduceus, with George and Martha slithering around it.

_Finally! _said George. _I haven't been full size in weeks!_

_ Oh, you're always complaining,_ said Martha.

Percy knew George and Martha were friendly, but he still had to resist the urge to flinch when Hermes brought the caduceus over his head. The snakes hissed and slithered up and down, and the wings over the caduceus began to glow and flutter.

"So what have you got?" said Hermes after a moment.

_Nothing!_ replied George. _We can't fix it._

_Well, not exactly 'nothing',_ said Martha. _It's true we can't fix it, and the boy's memory has been messed with all right, but there isn't any sign that any Olympian god has been here. Other than that, we have no idea what's wrong._

Something about the way Martha said that made Percy feel uneasy, but he couldn't put his finger on what.

Hermes nodded sagely. "I suspected as much. Well, Percy, I'm sorry I couldn't help. But perhaps you could talk to the Hypnos cabin back at camp. Memories are really more their area, and your friends themselves might be able to tell you more about what's been happening lately."

Percy almost smacked his own forehead. Why hadn't he thought of that?

"Well, we'd best be off," said Hermes. "I've some packages for Demeter, and she can get quite moody if they're late. Do let me know if you remember what you wanted to talk about."

_And don't forget my rat!_

_You're impossible, George, _said Martha._ Be seeing you, Percy!_

Hermes winked, then snapped his fingers and disappeared, taking his coke and sandwich with him.

Percy got up to leave, sure that some kind of monster was about to show up for no reason – that always happened when demigods went out in public – when he saw something that made him gasp and freeze in place.

He hadn't noticed it until now, but all the people in the cafeteria seemed to have a name floating over their heads, along with a line of numbers underneath. The letters and numbers were colored red, and waved and shifted like refracted holograms.

Percy rubbed his eyes to make sure he wasn't hallucinating, but when he looked again, the names and numbers were still there. That guy over there clearly had _Alex Wineson_ written over his head. The girl next to him, _Jamine Alvarez_. The family of four walking past them also had names floating over them. Percy realized they weren't just random names; they were the_ real names_ of the people they floated over. He didn't know how he knew that, but some part of him was sure that's what it was.

He looked up, expecting to see _Perseus Jackson_ floating over him, but the air above his head was clear of any writing. Did that mean whatever was happening was only happening to regular mortals, or was this some new ability of his, and it didn't work on himself?

_The backpack_, he thought. He didn't remember anything about it, so maybe it had some answers. He unzipped it with trembling fingers but the contents only gave him _more_ questions.

Inside, he found a pen – not riptide – Annabeth's cap of invisibility, a shiny red apple, a scrap of paper with the words 'Central Park, 5:00' written on it, and most confusing of all, a black notebook with eight names written inside it.

_Akira Kimura_

_Perseus Jackson – September 20__th_

_ Annabeth Chase – September 20__th_

_ Hazel Levesque – September 20__th_

_ Frank Zhang – September 20__th_

_ Jason Grace – September 20__th_

_ Piper McLean – September 20__th_

_ Leo Valdez – September 20__th_

Percy recognized seven of those names. Their owners had fought beside him against Gaea's forces not even a month ago. But who was Akira? He definitely had never heard that name before. And why was that name the only one without a date?

The cover of the notebook made things even _more_ confusing, and for some reason sent a chill down Percy's spine. In bold, capital letters, the cover read:

** DEATH NOTE**


	2. Another Note

**-Akira**

The apartment was large, dark, and messy. Hundreds of books littered the floor, piled high like anthills, and in the center of it all was a single clearing, on which sat a young man, illuminated by a headlamp perched on a nightstand.

The Death Note lay open on his crossed legs, seven new names freshly written on its pages, and every name written always meant one less evil on Earth.

But the boy frowned. These names were different. He could feel it. And though he'd expected it, a feeling of dissatisfaction still swept him. Humans had always been easy to kill. As easy as writing their name. But _these_ humans….

A throaty laugh sounded from the shadows. "Whose name are you writing this time?"

Akira looked briefly to the corner of the room. Gueki the Shinigami stood hidden in the shadows.

"Demigods don't die when I write their name in the Death Note," said Akira. "Can you tell me why that is?"

The Shinigami's head tilted. "Only a human whose name is written will die. The Death Note has no power over gods, and demigods are half god."

"Why, then, do demigods whose names I've written die of heart attacks anyway after some time has passed?"

"Easy," Gueki said, "half god or not, mortal is mortal. Their godly side might resist the power of the Note for a while, but in the end, the Death Note will always win." The death god's eyes gleamed in the darkness. "But you already know all this. Why do you ask?"

"I have a connection with my victims," said Akira, and he held open the Death Note for the Shinigami to see. "When I write a name, I can feel the moment that person's life reaches the end. Like the vibration of a sound wave." He set down the Note. "Demigods are different. Their deaths are like hourglasses. Those hourglasses appear the moment I write their names. Forty-five seconds later, the sand starts flowing. And when all the sand reaches the bottom, they die."

The Shinigami nodded. "Makes sense."

"This is where my current problem lies. You see, I've just written down the names of seven demigods. Percy Jackson, son of Poseidon, Annabeth Chase, daughter of Athena, Jason Grace, son of Jupiter, and… well, you remember them."

"They were the ones who fought the giants. What about them?"

"No hourglasses have appeared for them, and I wrote their names five minutes ago. For whatever reason, my Death Note doesn't affect them."

"They're supposed to be the strongest demigods of their generation," the Shinigami reasoned. "Maybe the Death Note needs more time."

"No," sighed Akira, closing the Note. "I doubt that's it. Demigods like Percy Jackson are powerful for sure. If all seven of them were like him, it would be a valid theory. But a demigod like Annabeth Chase, who's only useful trait is being clever, is definitely _not_ powerful. So we can rule out power as a possibility."

"I see... Well if power isn't the reason, then what is?"

"There are only five ways to survive the power of a Death Note." Akira counted off with his fingers. "One: the victim is younger than seven hundred and eighty days. Two: the victim is one hundred and twenty-four years old, or over. Three: The victim has less than twelve minutes of life remaining. Four: the victim's name has been misspelled four times, in which case, that person will be immune to the effects of that note."

Akira stood and stared pensively out the window.

"Right off the bat, we can disregard one and two," he went on. "And we've both seen the seven all have _well_ over twelve minutes left, so three's out too. That leaves us number four. And I know for a fact I've never misspelled a name. My eyes make sure of that…."

The Shinigami scratched his chin, looking a bit confused. "You said there were five ways to survive the Death Note. I know only of the four you mentioned. What's the fifth?"

A devilish smile crept over Akira's lips. "The fifth way to survive a Death Note… is to have your name already written on another."

For a long moment, the only sound was that of a car passing by.

"Where would another Death Note have come from?" asked the Shinigami, and there was a hint of skittishness in his voice.

"I can think of a few possibilities. Some more likely than others…" He turned to look at the death god. "Chiefly, there's an eighty-five percent chance there's _another_ Shinigami floating around here now."

"Impossible. No one knows of this place. It was pure happenstance that _I_ managed to stumble upon it."

"And that's exactly why I'm sure someone else has, too. Your presence here shows us at least _one_ Shinigami has found this world before. Who's to say another couldn't do the same?

The Shinigami considered this.

"Of course," Akira went on, "the real question is, who is holding the other Death Note? According to you, Shinigami just aren't interested in mortal affairs. I find it hard to believe one of them would just show up and start writing demigod names for no reason. So I think we can assume we're dealing with a dropped Note, and someone else – someone who is aware of the Greeks and Romans – picked it up and is currently using it to attack both factions."

Akira paced around the room, pensively staring at the ceiling. "Further, we can also surmise the Note user is an enemy of Olympus. Why else would they be attacking Olympians? Unless…"

Akira stopped suddenly. A worrying thought had occurred to him. An unlikely, dangerous, crazy sort of thought. A thought only another Note user could have the ability to put into action. But if Akira's thought was correct, it would mean he'd already been discovered… The other Note user wouldn't be _fighting_ the Olympians, they'd be _helping_ them….

"Eh? What are you thinking?" asked the Shinigami.

Akira snapped out of his thoughts.

No, he was just being paranoid, that was all. It was clear enough another Note user was at work here, Akira was sure of that. He _knew_ there was another Note user out there, but that didn't mean _they_ knew about _him…_.

"Something too unlikely," he told the death god. "An idea not even worth considering, so we won't."

Because surely no one would be dumb enough to write their own name in a Death Note and put the date of death at twenty-three days from now – the longest possible time the Death Note could wait – and certainly not _add the names of six of your friends along with yours_. Not to mention the fact this would mean an Olympian had gotten their hands on a Death Note, and not just _any_ Olympian, but one of the s_even. _And if the Olympian gods found out about it and discovered the pathway to the Shinigami realm….

Akira sighed. "For now, I'll work on the knowledge that there is another Note user, that they are working against Olympus, and that they don't yet know about me. These are the things I can safely deduce. Which begs the question…" He turned to look at the death god. "Are Shinigami able to detect one another?"

Akira had long figured out that Shinigami and Olympians didn't mix. One couldn't detect the presence of the other. He guessed the reason for this was the difference in their magic. Every world and every universe had its own rules, its own magic. And that magic couldn't account for anything that _wasn't_ part of its world. The Oracle of Delphi could thus make a prophecy of Greeks and Romans fighting Giants, because they were all part of the same world, but she _couldn't_ make a prophecy of Greeks and Romans fighting Shinigami, because Shinigami weren't part of that world. Magic simply couldn't see beyond its boundaries. Even if something happened to cross over.

So, Akira figured Shinigami wouldn't have a problem keeping track of one-another. After all, the Olympians could do it, so why not them?

Unfortunately, Akira's Shinigami shook its head in denial. "No. Even in the Shinigami realm, we don't have that ability. The only way we can locate something we can't see is to use a Viewing Hole. And those only exist in the Shinigami realm."

"Yes, the place you can't go back to. Meaning that option is off the table."

There was another silence.

Akira's plan was simple. Destroy the gods. Then wipe out their children and end their power completely. Then, when there was no one left to oppose him, kill all criminals on Earth. And certainly _not_ get caught doing it like the Kira before him.

But now, there was a new piece on the metaphorical chess board, and Akira had to deal with that _first_, if he wanted to avoid any nasty surprises.

"The biggest question right now," he said, "is _who_ is the other Note user? That's something I have to find out before I can put the rest of my plan into motion. Another Note means my biggest danger is having my name written. And I have to eliminate that threat."

"But how would you go about finding that person?" the Shinigami asked. "I can't track them, and Manhattan is a big place, if that's even where they are."

Akira thought for a moment.

That _was_ a problem. According to Gheki, the only way two Death Note users could identify one another was if they looked at each other through Shinigami eyes. Normally, you'd see a person's name and lifespan, but with a Note user, you'd only see their name. It was a simple enough test, complicated by the fact Manhattan was home to over one and a half million people, which was far too many to go through individually.

No, he needed to narrow down the results. He knew that, a) the Note user was attacking Olympians, therefore he knew, b) the Note user was familiar with the Greek and Roman worlds. That would mean the Note user had to be a demigod themselves, or a monster smart enough to figure out how to use it. It couldn't be a mortal, since they were all hopelessly ignorant when it came to magic, gods, and monsters… And he also knew, c) the Note user had written the names of the seven demigods that had ended the Giant war.

A monster made sense. They'd want revenge against the heroes who defeated Gaea.

Or perhaps a rogue demigod, like Luke Castellan had been…

A god wouldn't have any use for it. Not to mention Akira would be screwed if a god had the Note…

"I think… it's time we paid another visit to Camp Half-Blood."

**-Chiron**

Chiron paced restlessly around his office. The _clip-clop_ of his hooves echoed off the walls.

They were up to thirteen now. Thirteen missing demigods since the month of June had ended, and still no explanation.

It was never easy, but Chiron was used to it. For thousands of years he'd trained student after student, taught them the skills they needed to survive, taken them in as if they were his own children, only to see them venture to the outside world but never see them return.

As had been expected, many demigods had died from Gaea's bid for power. Some had perished when the camp was attacked, others while out on missions, and many more still from simply being at the wrong place at the wrong time outside of camp.

But through it all, every death, every disappearance, every loss was accounted for.

All except for these thirteen. No bodies had been recovered so far. They had not perished within the camp or outside it as far as anyone knew, and even Lord Hades could not account for their deaths, which possibly meant they were alive, somewhere.

No one had noticed until a few weeks ago, when demigods continued to disappear despite the war being over. Up until then, a proper count of those missing hadn't been possible, so disappearances were chalked up to Gaea and her forces. But it was nearly a month since the danger had passed, and still the disappearances occurred.

Scouts had been sent out, but nothing was ever found. Iris messages were attempted, but the goddess Iris could never find the recipients. Even Dionysus, who kept a watchful eye over the camp, couldn't tell where they'd gone.

Annabeth had suggested contacting Hermes. As the god of wanderers, she reasoned if anyone could find a lost soul, it was him. So she and Percy had burnt an offering, made a prayer, and gone off into the city, hoping Hermes would show.

That had been this morning, but it was nighttime now, and still there was no word from them. It usually wouldn't have worried Chiron too much – Percy and Annabeth were an unbeatable team. They _had_ managed to traverse Tartarus after all, a feat which, previous to them and Nico di Angelo, was completely unheard off, or even thought possible. Chiron was sure there was no monster Percy couldn't defeat, no problem Annabeth couldn't solve, and no threat or enemy they couldn't overcome together. The Fates were on their side far more than they had ever been with any demigod previous.

But now… Chiron couldn't help but feel afraid. He couldn't quite place his finger on what it was, but something strange was taking place. Something far worse than monsters, titans, or even giants – as terrifying as that was to consider.

There was a knock at the door.

"Come in," the centaur said.

The nob turned and Jason Grace poked his head through.

"You wanted to see me?"

Chiron gestured him to take a seat.

Jason looked like he'd just been dragged away from a sword fight. His pants and jacket were slashed open in places, his hair was a dusty mess and he was visibly sweaty. Ever since he'd made the switch to Camp Half-Blood, Jason had become a sort of mentor to the younger demigods. He personally oversaw camp training, made sure new demigods adjusted okay, and even kept all the cabins in order. _Mini Chiron_ some had begun to call him.

"Do you know why I've called you here?" Chiron asked him.

Jason's expression tightened. "It's about the disappearances, isn't it?"

Chiron nodded gravely. "We're up to thirteen now."

Jason looked at the floor. Chiron got the feeling the boy felt responsible for the missing demigods. Gradually, Jason was replacing Percy as the unofficial leader of the camp. Every loss probably felt like a personal failure to him. Like he was _supposed_ to protect everyone, and wasn't doing a very good job.

"Last I heard, it was twelve," said Jason. There was a twinge in his voice, like he was trying hard to keep his voice level. "Who's thirteen?"'

"Leslie Myers, daughter of Aphrodite."

Jason's hands tightened into fists, and Chiron's nearly did the same.

Leslie was nine years old and had arrived at camp only last week. Grover had rescued her from a pack of Telkhines after they'd chased her home from school. To even _imagine_ a child that young in danger was sad enough, but Leslie had quickly found herself a place in the hearts of everyone at camp. She was nice to a fault, wise beyond her years, and sweet and kind like a princess. She'd especially taken a shine to Piper, who she looked up to like a big sister. No doubt Jason had also grown personally attached. And now, she was gone…

"You said Hades confirmed none of them have passed through the Underworld," said Jason.

Chiron's throat felt dry.

"That means she's alive, and so are the others." Jason stood up. "Wherever they are, we'll find them. We need a prophecy. We should talk to Rachel, see what the Oracle has to say."

"Jason –"

"Three of us will go out and find out what happened. Percy and I disappeared once –"

"We can't go to Rachel –"

"– and no one could find us either, and it turned out we were both okay. This could just be one of the gods again, using us as pawns for something –"

"Jason, we can't ask Rachel for a prophecy."

"But _why not?_"

Chiron sighed. "Because we already have."

There was a silence.

"And…?" Jason asked tentatively.

Chiron threw his hands up. "Nothing," he said, and resumed pacing restlessly. "The Oracle of Delphi manifested as always, but when it did, there was nothing. No prophecy, no words, no riddle – nothing! My dear boy, I do not wish to alarm you, but do you realize the implications of such a thing?"

Jason was staring. His mouth opened, then closed, then opened again, but no words came out.

"It means," said Chiron, shutting his eyes tightly, "_even the Oracle of Delphi hasn't any idea what's going on._ Which is a thought so disconcerting, I have trouble bringing myself to believe it."

_Clip-clop, clip-clop_, went the centaur's hooves.

"Such a thing has never happened before," Chiron went on. "From the rise and fall of the Titans in ancient times, to the recent war with the giants, there has _always_ been a prophecy, Jason. I can't begin to imagine what forces could be at play now that even the Oracle has been silenced."

Jason looked like his brain was doing a million miles per hour.

Chiron hadn't meant to drop everything on him at once. He'd planned to space it out and explain the details in a slow, calmed manner. They'd warred with Kronos for half a decade, then gone straight to fighting Gaea with hardly any rest in between. And now, not even a month later, a new evil already seemed to loom on the horizon. There was only so much turmoil an old centaur could take…

"So what do we do?" Jason asked.

"That... is the real reason I called you here." Chiron cantered over to his desk and fished out an old-looking scroll from one of the drawers. "Percy and Annabeth departed camp this morning to meet with Hermes. There's a chance he might be able to shed some light on where our missing demigods have gone. Though, after this incident with the Oracle, I am no longer so sure… And so, I have a task for you, Jason. If you should choose to accept it."

"Anything," the boy said immediately.

"Your bravery and loyalty to this camp are well noted, son of Jupiter. But do not be so rash to agree to an unknown task. The quest I have in mind would be a considerably dangerous undertaking. Something not even the gods have ever attempted before."

A grave sort of smile formed on Jason's lips. "Even more dangerous than Gaea?"

Chiron stroked his beard absently. "Not quite, I'd say. But terribly dangerous, nonetheless. I'm not sure the gods would be happy with it, but some part of me is convinced it's the right thing to do."

"Chiron, if it can get our friends back, it's not even a question." Jason nodded. "I accept the quest."

_Brave, rash, and loyal_, Chiron couldn't help but think. Now who did THAT remind him of?

The old centaur smiled and handed Jason the scroll.

"Your quest, Jason Grace … is to seek out the Sisters of Fate."

-**Percy**

It was two minutes till five o'clock, and Percy Jackson was wandering aimlessly through central park with a million questions in mind.

Where was Annabeth? Why couldn't he remember anything? What was that weird notebook in his backpack, and _why were people's names floating over their heads_?

He sat down hard on a bench and tried not to freak out.

Percy and Annabeth had promised each other – as they fell down the pit of Tartarus – that they'd never be apart again. And yet here they were, apart again. That was bad enough. But of course, it wasn't all.

Something else was bothering Percy. A feeling he couldn't quite explain. A similar kind of sensation he'd experienced not too long ago, when he'd fought over the ice of Antarctica. A feeling of…

… of Death.

Somewhere, a bell tolled, and then several things happened at once.

A shadow fell over Percy.

Black feathers rained from the sky in a gust of wind.

A hissing laughter pierced the air.

A pair of black boots touched down on the pavement with an owner six feet tall, and Percy knew in a heartbeat that he was looking at a god.

Skin pale as a corpse. Black wings the size of Blackjack's. Yellow eyes with blood-red irises. A familiar-looking notebook with a metal cross on the cover hung at his side.

The god smiled at Percy with pointed teeth.

"You must be Percy," he said. "My name is Ryuk. I was told you have an apple for me?"

**A/N: A few of you messaged me and asked I make longer chapters. While I do have the major plot points of the story plotted, the story is more-or-less writing itself. I don't want long chapters for the sake of long chapters, but if the scene calls for it, they'll happen. ;)**

**So anyways, if you like or don't like the story, be sure to leave a review. It lets me know if people are enjoying it, or if there's room for improvement. Until next chapter, peace out.**


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